How can i change the original template of ConversationalRetrievalChain ?

[tarek-kerbedj]

Hello everyone, I have implemented a ConversationalRetrievalChain that deals with stored documents and I did receive good initial results, but I want to change the original template and I couldn't find any guide on how to do it

[oddrationale]

I'm assuming you mean you want to change the default prompt for the ConversationalRetrievalChain. If so, you can do that by setting the combine_docs_chain_kwargs:

from langchain.chains import ConversationalRetrievalChain
from langchain.chat_models import ChatOpenAI
from langchain.memory import ConversationBufferMemory
from langchain.prompts import (
    ChatPromptTemplate,
    HumanMessagePromptTemplate,
    SystemMessagePromptTemplate,
)


system_message_prompt = SystemMessagePromptTemplate.from_template(
    "Answer the user question based on the context:\n{context}"
)
human_message_prompt = HumanMessagePromptTemplate.from_template(
    "{question}"
)

chain = ConversationalRetrievalChain.from_llm(
    llm=ChatOpenAI(temperature=0),
    retriever=vectorstore.as_retriever(),
    memory=ConversationBufferMemory(
        memory_key="chat_history",
        return_messages=True,
    ),
    combine_docs_chain_kwargs={
        "prompt": ChatPromptTemplate.from_messages([
            system_message_prompt,
            human_message_prompt,
        ]),
    },
)

I believe you need to make sure your custom prompt includes the {context} and {question} variables. Not 100% sure if the chain expects those variables.

Hope that helps!